ABSTRACT
Due to the increasing resistance of various Candida species to azole drugs, particularly fluconazole, it would be of significant importance to look for alternative therapies. The aim of this study was to investigate the antifungal activity of capric acid and its in vitro interactions with nystatin and fluconazole against Candida isolates. A total of 40 Candida isolates (C. albicans, 36; C. kefyr, 2; C. tropicalis, 1; C. glabrata, 1) collected from the oral cavity of neonates with oropharyngeal candidiasis and a reference strain of C. albicans (ATCC 10231) were used in this study. Antifungal activity of capric acid and two comparator antifungal drugs, namely fluconazole and nystatin, was tested according to CLSI M27-A3/M60 method. The in vitro interaction between capric acid with fluconazole and nystatin was determined following a checkerboard method and results were interpreted using fractional inhibitory concentration index. Nystatin had the lowest minimum inhibitory concentrations (range, 0.125-8 µg/mL; geometric mean [GM], 0.6229 µg/mL) followed by fluconazole (range, 0.5-16 µg/mL; GM, 1.9011 µg/mL) and capric acid (range, 128-2,048 µg/mL; GM, 835.9756 µg/mL). When tested in combination, capric acid with fluconazole demonstrated synergistic, indifferent, and antagonistic interactions in 3 (7.317%), 24 (58.536%), and 14 (34.146%) cases, respectively. For combination of capric acid with nystatin, synergistic, indifferent, and antagonistic interactions were observed in 1 (2.439%), 19 (46.341%), and 21 (51.219%) cases, respectively. All cases of synergistic interactions were against resistant or susceptible dose-dependent isolates. Fluconazole, nystatin, and capric acid seem to be more effective when they are used alone compared with their combination. However, their combination might be effective on resistant isolates.
Subject(s)
Antifungal Agents/pharmacology , Candida/drug effects , Candidiasis, Oral/drug therapy , Decanoic Acids/pharmacology , Fluconazole/pharmacology , Nystatin/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Candida/isolation & purification , Candidiasis, Oral/microbiology , Decanoic Acids/chemistry , Decanoic Acids/isolation & purification , Dose-Response Relationship, Drug , Fluconazole/chemistry , Fluconazole/isolation & purification , Humans , Microbial Sensitivity Tests , Nystatin/chemistry , Nystatin/isolation & purificationABSTRACT
We investigate the dispersion properties of TE-polarized surface plasmon polaritons at the interface of a strained graphene cladded one-dimensional photonic crystal and a homogeneous medium. The optical conductivity of graphene under uniform planar tension is numerically calculated using the perturbation theory and the nearest-neighbor tight-binding approximation. We show that the wavelength, propagation length, and penetration depth of the surface plasmon polaritons in the homogeneous environment and the photonic crystal depend on the magnitude and orientation of the applied strain. Depending on the magnitude and direction of the tension, a Van Hove singularity may appear at the electronic band structure of the graphene in the desired frequency interval. We show that the surface mode corresponding to the Van Hove singularity has the least propagation length. We also observe that strain only affects the penetration depth of the low-frequency surface plasmon polaritons in the homogeneous medium and the high-frequency surface plasmon polaritons in the photonic crystal.
